Comparison of the effectiveness of radiotherapy with photons, protons and carbon-ions for non-small cell lung cancer: A meta-analysis

Purpose: To provide a comparison between radiotherapy with photons, protons and carbon-ions in the treatment of Non-Small-Cell Lung Cancer (NSCLC), performing a meta-analysis of observational studies. Methods: Eligible studies on conventional radiotherapy (CRT), stereotactic radiotherapy (SBRT), concurrent chemoradiation (CCR), proton therapy and carbon-ion therapy were searched through a systematic review. To obtain pooled estimates of 2- and 5-year disease-specific and overall survival and the occurrence of severe adverse events for each treatment modality, a random effects meta-analysis was carried out. Pooled estimates were corrected for effect modifiers. Results: Corrected pooled estimates for 2-year overall survival in stage I inoperable NSCLC ranged from 53% for CRT to 74% for carbon-ion therapy. Five-year overall survival for CRT (20%) was statistically significantly lower than that for SBRT (42%), proton therapy (40%) and carbon-ion therapy (42%). However, caution is warranted due to the limited number of patients and limited length of follow-up of the particle studies. Conclusion: Survival rates for particle therapy were higher than those for CRT, but similar to SBRT in stage I inoperable NSCLC. Particle therapy may be more beneficial in stage III NSCLC, especially in reducing adverse events.